prepared materials were packed in 7 mL irradiation vials, or 'rabbits', six or seven micro- .... SEB, DBG, EINP, as well as in the living layer (LL) taken from 8 peat cores ... 6. 9. 12. 15. 18. 21. As/S c. Mean. Mean±SD. Min-Max. Outliers. ABS. UTK ..... 0.43. 0.26. 0.37. 0.07. 1.21. 0.04 0.02. 0.03. 0.03. 0.06. 0.47. 0.18. 0.51. 0.10.
SUPPLEMENTARY DATA Dust is the dominant source of “heavymetals” to peat moss (Sphagnum fuscum) in the bogs of the Athabasca Bituminous Sands region of northern Alberta Instrumental Neutron Activation Analysis (INAA) INAA of selected samples and standard reference materials was performed at the University of Alberta SLOWPOKE-II Nuclear Reactor Facility. Aliquots of samples and standards, each weighing between 140 – 230 mg, were accurately weighed into individual nitric acid washed 300mL polyethylene micro-centrifuge tubes, tamped, and hermetically sealed. The prepared materials were packed in 7 mL irradiation vials, or ‘rabbits’, six or seven micro-tubes per irradiation vial, and irradiated for 4 hours at a nominal thermal neutron flux of 5 x 1011 n cm- 2 s-1
in an inner site of the SLOWPOKE Nuclear Reactor. After irradiation the induced
radioactivity in each sample was measured a minimum of three times over the following four weeks using a 40% relative efficiency ORTEC FX-Profile hyperpure Ge detector with carbon window, attached to an ORTEC DSPEC Pro digital spectrometer. Measurements were made following a decay period of ~1day, ~7 days, and ~3 weeks to maximize the number of elements determined. Upon completion of the long decay measurements, and a total decay period of at least 39 days, samples and select standards were individually re-irradiated in an inner site of the SLOWPOKE Nuclear Reactor for 240 seconds at a nominal thermal neutron flux of 5 x 1011 n cm-2
s-1
for the purpose of measuring the concentration of those elements which only produce
short-lived radionuclides following neutron irradiation in a nuclear reactor (e.g., Al, V). Following an accurately timed decay period of 120 to 240 seconds each sample was counted for 240 seconds at a sample-to-detector distance of 16 cm utilizing the same 40% relative efficiency ORTEC FX-Profile hyperpure Ge detector and digital spectrometer noted above. Samples were each counted in real-time with the spectrometer in zero dead time mode for loss free counting.
1
Element quantification was performed by the semi-absolute comparator method of NAA (Bergerioux et al., 1979) using a variety of standard reference materials of known composition from NIST and IAEA, for example, for either calibration or QA/QC purposes. The strong linear correlations obtained between Sc and Al as well as Sc and Th (Supporting Data, Figure 1) support the use of Sc as conservative, lithophile element for calculating the crustal Enrichment Factor (EF). Principal Component Analysis Principal Component Analysis (PCA) was performed on the correlation matrix of the trace element concentrations using Matlab R2010a both for all samples, as well as the samples from the ABS region only. Some elements (Pd, Se, and Te) were removed from the original dataset due to a high number of values < LOD; the remaining 51 concentrations with values < LOD were replaced with zeros. The number of significant principal components (PCs) associated with each dataset was determined by examining the scree plots (Supporting Data, Figures 4A, B). Using this approach (Joliffe, 2002) it was thereby determined that four and two PCs were the most appropriate for describing the variation in the full and ABS-only datasets, respectively. Complete loading vectors for the significant PCs of the full and ABS-only datasets are shown in Supporting Data Tables 7 and 8, respectively. It is apparent from the score plots of PC1 vs PC2 for the full dataset that the majority of the variation along PC1 described differences amongst the relatively large number of ABS and Wagner samples, and also described location-specific differences between samples for the other locations (Supporting Data Figure 5a). PC2 distinguished the living layers (LL), Wagner, and DBG (negative scores) from ABS and EINP (positive scores), while the samples from SEBA
2
were spread between these groups. In the score plot for the ABS-only dataset, the variation described by PC1 was primarily associated with the S-series of mosses scattered throughout the ABS region (Supporting Data Figure 3b; see also Figure 1, location map). PC1 also served to distinguish samples from Utikuma from all other samples (scores < -7).
SUPPLEMENTARY DATA REFERENCES Bergerioux C., Kennedy G. Zikovsky L., 1979. Use of the semi-absolute method in neutron activation analysis. J. Radioanal Chem., 50:229-234. Jolliffe I.T., 2002. Principal Component Analysis (2nd ed.). Springer-Verlag New York Inc., NY, 487pp.
3
1.8
12
1.2
8
V (mg kg-1)
Pb (mg kg-1)
SD Figure 1. Linear regression of trace metal concentrations (Pb, V, Ni, Mo, Ag, Cd, Sb, Tl) in Sphagnum fuscum from the ABS region, versus Th. Moss samples collected at Utikuma (UTK, control site) are shown using triangles.
0.6
4
y = 0.0017x + 0.3372 R² = 0.7608, p = 0.000 (n = 78)
y = 0.0122x + 0.4836 R² = 0.8644, p = 0.000 (n = 78) 0
0.0 0
200
400 Th (μg kg-1)
600
0
800
200
400 Th (μg kg-1)
600
800
600
800
0.8
4
y = 0.0007x + 0.1064 R² = 0.7327, p = 0.000 (n = 78) 0.6
Mo (mg kg-1)
Ni (mg kg-1)
3
2
0.4
0.2
1 y = 0.0042x + 0.5402 R² = 0.8265, p = 0.000 (n = 78)
0.0
0 0
200
400 Th (μg kg-1)
600
0
800
200
120
100 y = 0.0937x + 13.163 R² = 0.6867, p = 0.000 (n = 78)
Cd (μg kg-1)
Ag (μg kg-1)
y = 0.0158x + 33.805 R² = 0.0546, p = 0.040 (n = 78)
90
75
50
60
30
25
0
0 0
200
400 Th (μg kg-1)
600
0
800
200
400 Th (μg kg-1)
600
800
600
800
60
150
y = 0.052x + 4.1704 R² = 0.8507, p = 0.000 (n = 78)
y = 0.0711x + 19.989 R² = 0.3535, p = 0.000 (n = 78)
100
Tl (μg kg-1)
Sb (μg kg-1)
400 Th (μg kg-1)
50
40
20
0
0 0
200
400 Th (μg kg-1)
600
800
0
200
400 Th (μg kg-1)
SD Figure 2. Box plots showing: mean and range in element/Sc ratio for chalcophile and biophile trace metals (Ag, As, Bi, Cd, Cu, Mo, Ni, Pb, Sb, Tl, V, Zn) in moss from ABS, UTK, WAG, SEB, DBG, EINP, as well as in the living layer (LL) taken from 8 peat cores collected across Canada. 1.4
21 Mean Mean±SD Min-Max Outliers
0.8
15 As/Sc
0.6
1.0
12 9
0.4
0.2
3
0.2
UTK
3.5
WAG
SEB
DBG
EINP
0
LL
2.5
ABS
UTK
WAG
SEB
DBG
EINP
120
Mean Mean±SD Min-Max Outliers
3.0
0.0
LL
Cu/Sc
1.0
60
10
40 20
ABS
UTK
WAG
SEB
DBG
EINP
0
LL
60 50
120 100 Pb/Sc
40 Ni/Sc
ABS
UTK
WAG
SEB
DBG
EINP
30
60
WAG
SEB
DBG
EINP
0
LL
ABS
UTK
WAG
SEB
DBG
EINP
35
V/Sc
0.6
0.3
0.0 ABS
UTK
WAG
SEB
DBG
EINP
LL
EINP
LL
WAG
SEB
DBG
EINP
LL
Mean Mean±SD Min-Max Outliers
ABS
UTK
700 600
25
500
20
400
15
300
10
200
5
100 ABS
UTK
WAG
SEB
5
DBG
EINP
LL
Mean Mean±SD Min-Max Outliers
800
30
0
DBG
900 Mean Mean±SD Min-Max Outliers
40
0.9
SEB
1.2
0.0
LL
Zn/Sc
1.2
Mean Mean±SD Min-Max Outliers
WAG
0.4
45
1.5
UTK
0.8
20
UTK
ABS
1.6
40
ABS
LL
6
2.0
80
0
EINP
2.4 Mean Mean±SD Min-Max Outliers
20 10
DBG
8
0
LL
140 Mean Mean±SD Min-Max Outliers
SEB
2
Sb/Sc
-0.5
WAG
4
0.5 0.0
UTK
Mean Mean±SD Min-Max Outliers
12
80
1.5
ABS
14
Mean Mean±SD Min-Max Outliers
100
2.0
Tl/Sc
0.6
6
ABS
Mean Mean±SD Min-Max Outliers
0.8
0.4
0.0
Cd/Sc
1.2
Mo/Sc
Ag/Sc
1.0
18
Bi/Sc
1.2
1.4 Mean Mean±SD Min-Max Outliers
0
ABS
UTK
WAG
SEB
DBG
EINP
LL
SD Figure 3. Linear regression of Sc against Al and Sc against Th for triplicate moss samples from MIL, EINP and UTK measured using INAA.
Sc vs. Th - INAA (Alberta mosses) 600
Sc (ug/kg)
500 400 300 200 y = 0.9637x + 2.1314 R² = 0.99755
100 0 0
100
200
300
400
500
600
700
Th (ug/kg)
Sc vs. Al - INAA (Alberta mosses) 700
Sc (ug/kg)
600 500 400 300 200
y = 0.1968x - 6.7996 R² = 0.9979
100 0 0
500
1000
1500
2000
Al (mg/kg)
6
2500
3000
3500
SD Figure 4. Screen plots showing the variance explained by the first 20 components for A, all samples and B, ABS region only.
A
18
B
25
Variance explained
16 20
14 12
15
10 8
10
6 4
5
2 0
0 0
10 Number of components
20
0
7
5 10 15 Number of components
20
SD Figure 5. PC1 vs PC2 score plots for A all sites, and B ABS sites only. Plot A: ABS, WAG, SEB, LL, EINP, DBG. Plot B: Moss (‘S’-series), ANZ, JPH4, MIL, McK, McM, UTK.
A
B 5
7 6
-5
0
5
10
PC2 (5.9 % of variation explained)
PC2 (17.1% of variation explained)
0 -10
15
-5
-10
-10 -15
5 4 3 2 1
0 -5
0
5
10
-1 -2
-20 PC1 (50.6% of variation explained)
-3 PC1 (71.0 % of variation explained)
8
15
SD Table 1. List of all moss samples included in this study. Locations where moss only was collected (S1 to S 20 by Dr. Melanie Vile on July 20 and 21, 2013; see Shotyk et al., 2014 for details) are listed separately from sites where moss plus peat cores were collected (by W.S.): in 2013 on August 6 (ANZ) and August 7 (JPH-4), on October 16 (MIL) and October 17 (McK) as well as in 2014 on September 15 (McM) and on September 18 (UTK). Also listed are the locations of the four bitumen upgraders of the ABS region, namely (from N to S) CNRL, Syncrude, Suncor and Nexen. The mid-point between the Suncor and Syncrude upgraders is commonly taken as the geographic centre of the ABS region.
Moss only collected
S1 S2 S3 S4 S5 S6 S7 S8 S9 S10 S11 S12 S13 S14 S15 S16 S17 S18 S19 S20 WAG SEB EINP
57° 7'7.63" N 57° 17'21.70" N 57° 2'2.40" N 56° 49'35.73" N 56° 48'19.54" N 57° 13'9.63" N 57° 19'35.20" N 57° 15'42.78" N 57° 8'53.62" N 56° 48'53.27" N 56° 50'51.16" N 56° 56'13.69" N 56° 59'50.80" N 56° 44'38.25" N 56° 45'49.59" N 56° 52'39.58" N 56° 59'17.20" N 56° 59'7.80" N 57° 5'8.32" N 57° 9'3.18" N 53° 34'11.06" N 53° 26'6.23" N 53° 38'33.1" N
111° 49'15.80" W 111° 47'48.60" W 112° 3'8.42" W 112° 9'18.26" W 111° 50'22.02" W 112° 5'9.92" W 111° 19'35.90" W 111° 19'22.86" W 111° 25'39.04" W 111° 17'12.08" W 111° 47'52.38" W 111° 43'18.26" W 111° 50'9.60" W 111° 47'16.20" W 111° 30'2.13" W 111° 3'46.41" W 111° 13'53.00" W 111° 6'6.10" W 111° 31'24.60" W 111° 4'11.15" W 113° 49'112.3" W 114° 52'6.48" W 112° 51'33.0" W
Distance from midpoint (km) 19.6 33.1 30.7 43.1 30.2 39.2 36.2 29.7 15.6 28.3 24.9 14.4 17.8 34.5 29.2 33.7 19.6 27.4 6.9 32.2 410.4 447.8 389.8
Moss and peat cores collected
MIL JPH-4 McK McM ANZ UTK
56° 55'50.4" N 57° 6'44.10" N 57° 13'42.4" N 56° 37'40.4" N 56° 28'19.08" N 56° 04'34.6" N
111° 28'30.3" W 111° 25'24.42" W 111° 42'00.8" W 111° 11'39.1" W 111° 2'33.66" W 115° 28'31.2" W
11.0 12.4 24.9 48.7 68.4 263.8
Syncrude stack Suncor stack CNRL stack Nexen stack Midpoint
57° 2'25.8" N 111° 37'9.12" W 57° 0'11.88" N 111° 27'57.9594" W 57° 20'7.4394" N 111° 45'20.16" W 56° 24'42.12" N 110° 56'15.36" W 57° 1'18.9228" N 111° 32'33.399" W
Latitude
Longitude
9
5.0 5.0 37.2 77.4 0
SD Table 2. List of peat cores from various locations across Canada (Fig. 1). These cores were collected as part of past studies (references cited) which were used to provide the living layer (LL) analyzed for the current study.
Province
Name of bog (core and sample)
Coordinates
Date of collection
Remarks
Reference
British Columbia
Drizzle Bog (QCI 02)
53.92772′ N 132.10574′ W
14 Jul. 2003
Graham Island, Haida Gwai (formerly Queen Charlotte Islands)
Huntley et al. (2013)
Ontario
Sifton Bog (SIF 01)
42° 58’31" N 81° 19’48" W
27 Jul. 2000
London
Givelet et al. (2003)
Luther Bog (LUT 01)
43° 54’30" N 80° 24’36" W
26 Jul. 2000
Luther Marsh Conservation Area
Givelet et al. (2003)
Spruce Bog (ALG 01)
45° 35’51" N 78° 22’16" W
10 Jul. 2000
Algonquin Park
Givelet et al. (2003)
Spruce Bog (ALG-3)
45° 35’51" N 78° 22’16" W
Oct. 1992
Algonquin Park
Givelet et al. (2003)
Kuujjuarapik (NQT 03 01)
55° 13’32.0" N 77° 41’44.4" W
19 Jul. 2003
NQT-3
Kuujjuarapik (NQT 04 01)
55° 13’33.0" N 77° 41’49.6" W
19 Jul. 2004
NQT-4
Point Escuminac (PEW 1.1)
46° 55' N 65° 30' W
20-22 Nov. 1996
PEW-1
Quebec
New Brunswick
10
Givelet, N. (unpublished field report) Givelet, N. (unpublished field report)
Weiss et al. (2002)
SD Table 3. Average, standard deviation, median, minimum and maximum concentration (mg/kg or µg/kg) of trace elements in the moss samples from the ABS region, Utikuma (UTK), Wagner Wetland (WAG), Seba Beach (SEB), the herbarium collection of the Devonian Botanical Garden (DBG) and Elk Island National Park (EINP). ABS (n = 75) Unit
LOD
Avg.
St. dev.
Median
UTK (n = 3) Min
Max
Avg.
St. dev.
Median
WAG (n = 15) Min
Max
Avg.
St. dev.
Median
SEB (n = 12) Min
Max
Avg.
St. dev.
Median
DBG (n = 5) Min
Max
Avg.
St. dev.
Median
EINP (n = 3) Min
Max
Avg.
St. dev.
Median
Min
Max
Ag
µg/kg
1
39.1
18.5
36.0
9.0
91.0
4.3
0.9
5.0
3.0
5.0
45.5
26.3
46.0
12.0
105.0
16.3
4.5
17.5
5.0
22.0
16.0
4.8
17.0
7.0
21.0
7.0
1.4
6.0
6.0
9.0
As
mg/kg
0.005
0.43
0.26
0.37
0.07
1.21
0.04
0.02
0.03
0.03
0.06
0.47
0.18
0.51
0.10
0.77
0.24
0.08
0.25
0.10
0.40
0.17
0.05
0.14
0.13
0.24
0.10
0.01
0.09
0.08
0.11
Ba
mg/kg
1
24.6
11.5
22.0
9.0
59.0
12.0
0.8
12.0
11.0
13.0
39.3
12.2
42.0
14.0
56.0
20.5
6.4
20.0
14.0
38.0
21.8
8.8
20.0
12.0
33.0
22.0
2.9
21.0
19.0
26.0
Be
µg/kg
0.1
49.9
28.3
43.0
15.0
126.0
10.3
3.3
10.2
6.3
14.4
42.4
16.2
45.8
10.7
74.6
36.4
24.2
25.4
20.8
103.0
13.8
3.8
12.9
9.6
20.9
13.4
2.9
11.9
10.9
17.5
Bi
µg/kg
1
12.8
9.6
10.0
4.0
64.0
n.d.
n.d.
n.d.
